Conowingo Dam Gates Opened, But Impact Could Be Minimal

Dam operators opened four of Conowingo Dam's 53 flood control gates Thursday to relieve pressure from Hurricane Sandy's record-breaking downpour.

The gates began to open Tuesday and Wednesday, and more were opened Thursday. When more than 40 of the floodgates were opened in September 2011, following Hurricane Irene and Tropical Storm Lee, the resulting debris was carried from the Susquehanna River in northeast Baltimore down to nearly all areas of the Chesapeake Bay.

Environmental groups . The event also spurred talk of how to handle wastewater runoff in the state after the introduction of the Environmental Protection Agency's Chesapeake Bay pollution diet.

Debris is expected to begin showing up along the shorelines of the Chesapeake Bay in the coming weeks.

Kathleen Mooneyhan, of the Cape St. Claire Improvement Association, took part in clean-up efforts at the Cape's community beaches last year.

"We are very concerned about the impact that the debris released into the Bay after the opening of the dam will have on Cape St. Claire, and are watching closely," she said. "Unfortunately, the last time this happened, we expended a lot of time and effort on cleanup."

But this year's floodgates shouldn't carry the same level of destruction for Chespeake Bay's waterways, said West/Rhode Riverkeeper Chris Trumbauer.

"I certainly don't expect this to be anything like what we saw after Irene and Lee last year. That was a one-two punch," Trumbauer said. "There will be an effect, but I don't expect it will be as big a deal."

Sandy broke rainfall records along the East Coast, but most of it occurred in central Maryland, not north of the Susquehanna River, which means the impact from the dam won't be as significant as 2011's storm events, Trumbauer said.

Sandy also appeared later in the season than Irene, which means lower temperatures have caused underwater grasses to go dormant, lowering the potential for damage to them. 

Trumbauer, who is also the District 6 representative on the Anne Arundel County Council,  has been out on the West and Rhode rivers this week, doing water quality assessments. He said Sandy didn't hit Annapolis nearly as hard as it could have.

"We didn't see a lot of high water damage or erosion in our rivers, which is fortunate," he said. "It will be interesting to see how the downriver water quality is affected in the coming [days and weeks] as all the runoff moves down the Bay."